Factors associated with discordance between absolute CD4 cell count and CD4 cell percentage in patients coinfected with HIV and hepatitis C virus.

BACKGROUND: Liver cirrhosis has been associated with decreased absolute CD4 cell counts but preserved CD4 cell percentage in human immunodeficiency virus (HIV)-negative persons. We evaluated factors associated with discordance between the absolute CD4 cell count and the CD4 cell percentage in a cohort of patients coinfected with HIV and hepatitis C virus (HCV).
METHODS: Baseline data from 908 participants in a prospective, Canadian, multisite cohort of individuals with HIV-HCV coinfection were analyzed. Absolute CD4 cell count and CD4 cell percentage relationships were evaluated. We defined low and high discordance between absolute CD4 cell count/CD4 cell percentage relationships as CD4 cell percentages that differed from the expected CD4 cell percentage, given the observed absolute CD4 cell count, by ±7 percentage points; we defined very low and very high discordance as differences of ±14 percentage points. Factors associated with high or very high discordance, including either end-stage liver disease or aspartate transaminase to platelet ratio index (APRI) of >1.5, were analyzed using multivariate logistic regression models and compared to groups with concordant and low discordant results.
RESULTS: High/very high discordance was seen in 31% (n = 286), while 35% (n = 321) had concordant values. Factors associated with very high discordance at baseline included history of end-stage liver disease (adjusted odds ratio [aOR], 6.52; 95% confidence interval [CI], 2.27-18.67) and APRI of >1.5 (aOR 4.69; 95% CI, 1.64-13.35). Compared with those with detectable HCV RNA, those who cleared HCV spontaneously were less likely to have very high discordance.
CONCLUSIONS: Discordance between absolute CD4 cell count and CD4 cell percentage is common in an HIV/HCV-coinfected population and is associated with advanced liver disease and ongoing HCV replication.